Hitherto, there are used image pick-up apparatuses using CCD (Charge Coupled Device) type image pick-up device as solid-state image pick-up device. The image pick-up apparatuses of this kind are adapted to control read-out timings of charges stored (accumulated) in the CCD image pick-up device to thereby increase charge storage time of charges stored in the CCD image pick-up device to perform long time exposure thus to have ability to pick up an image of an object at high density.
For a time period during which charges are being stored into the CCD type image pick-up device for the purpose of performing long time exposure, it is impossible to read out charges from the CCD type image pick-up device. Accordingly, images temporarily stored in a memory are outputted for charge storage time period of the CCD type image pick-up device to perform complementary processing of such image.
Techniques as described below are proposed in regard to complementary processing of image for long time exposure period.
First, in the Japanese Patent Application Laid Open No. 1997-168118 publication, there is proposed a technique of reading out charges on one field basis from the CCD type image pick-up device to store images of one field (one even field or one odd field) into a memory (field memory), and to read out images of one field from the memory for a long time exposure period to perform complementary processing of such image.
Moreover, in the Japanese Patent Application Laid Open No. 1997-252423 publication, there is proposed a technique of reading out charges on one frame basis by the so-called frame read-out operation from the CCD type image pick-up device to store images of one frame into a memory (frame memory) to read out images of odd field from the memory at a timing where image of odd field is outputted for a long time exposure period to perform complementary processing of such image, and to read out images of even field from the memory at a timing where image of even field is read out during such time period to perform complementary processing of such image.
In the technique described in the Japanese Patent Application Laid Open No. 1997-168118 publication, images of even field or odd field are stored into a field memory to read out the images of even field or odd field stored in the field memory at the time of long time exposure to perform complementary processing thereof. Accordingly, in the case where this technique is applied to equipments based on the existing television standard in which interlaced scanning is performed, there is the problem that since the same images would be outputted both at even field and at odd field as image at the time of long time exposure, vertical resolution is halved so that this technique is not practically useful with respect to moving images.
In addition, at both the techniques described in the Japanese Patent Application Laid Open No. 1997-168118 publication and the Japanese Patent Application Laid Open No. 1997-252423 publication, since it is necessary for picking up image of object at a high sensitivity to elongate charge storage time of the CCD type image pick-up device, there would result image having large movement or vibration with respect to moving object. Even if focusing adjustment is made, or adjustment of brightness is performed in order to eliminate such movement or vibration, time lag with respect to adjustment takes place because complementary processing is performed by stored images. Thus, adjustment becomes very difficult. As a result, it is impossible to acquire an image having picture quality such that user expects even if sensitivity is raised.